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Becca Calhoun's avatar

Good article on the chemistry of carbon dioxide's concentration in the atmosphere to create heat. 350 ppm has been the popular determined point at which the concentration becomes a problem for plants & animals. And it gets exponentially worse with more carbon molecules dumped into the atmosphere & ocean. I have always had trouble visualizing the unit size of one million molecules of atmosphere. I have not found a satisfying answer anywhere. Not sure that is relevant to climate change mitigation/adaptation. Just curious.

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Alastair Williams's avatar

It's a good question! Scientists often talk about things in a way that is hard to visualise, and I think that makes it hard for people to really understand what they are saying.

In each million molecules of the air around us, roughly 780,000 are nitrogen atoms. 210,000 are oxygen, and 9,000 are argon. The rest is split between carbon dioxide and other gases like helium and methane. That million molecules fills an incredibly small volume, however - so small that we couldn't really see it. In reality, an average room contains trillions upon trillions of molecules - vastly more molecules than there are stars in the universe.

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Becca Calhoun's avatar

Thanks for the explanation. It's hard to wrap my mind around how tiny the ppm's in the atmosphere amount to. In everyday climate change discourse we talk about the amounts of gases like they were gumballs in a dispenser. I honestly envisioned a million molecules of atmosphere as a cubic foot of space.

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